1. Field of the Invention
The present invention relates to a method of using a memory in which an efficient SIMD (Single Instruction stream Multiple Data stream) operation can be implemented, a two dimensional access memory embodied as an instrument with this method of using the memory, and an operation processing apparatus that can perform the SIMD operation efficiently employing the two dimensional data access memory.
2. Description of the Related Art
The SIMD operation is involved in having a plurality of processors and processing plural pieces of data on the same instruction. Therefore, the SIMD operation is very efficient to perform the parallel operation by taking out a partial row of continuous data from one dimensional row of data stored in memory.
However, when the data to be operated is not stored continuously in the memory, or the operation result is to be arranged discretely at predetermined locations in the memory, it is required to have a processing for preparing for the data subject to parallel operation and a processing for arranging the parallel operation result at predetermined locations in the memory. Therefore, there is the disadvantage that the intrinsic parallel operation may be hampered.
By the way, a technique for speeding up the two dimensional discrete cosine conversion with the SIMD processing was described in Japanese Patent Laid-Open No. 2000-69478.
With this technique, the image data arranged in a scanning order is rearranged in the order suitable for executing a butterfly operation in the conversion encoding operation through the SIMD processing, the rearranged result being stored in the memory, and the image data stored in the memory is subjected to two dimensional cosine conversion.
However, in the technique as described in the above-cited patent, an operation for rearranging the image data is required, and when implemented in hardware, a circuit involving rearranging operation is needed, resulting in the larger circuit scale and the increased consumption power due to the memory access for the rearranging operation.